Back
Cordosphaeridium latum
Cordosphaeridium latum (Klumpp, 1953) Lentin and Williams, 1985; emend. Sarjeant, 1981
Originally Hystrichosphaeridium diktyoplokus ssp. Iatum, subsequently Cordosphaeridium diktyoplokus ssp. Iatum, thirdly Areosphaeridium diktyoplokus ssp. Iatum, fourthly Plethysyrinx lata, fifthly (and now) Cordosphaeridium latum.
Lentin and Williams, 1985, did not accept the emendation of this species by Sarjeant, 1981.
Holotype: Klumpp, 1953, pl.18, figs.8-9; and figured by Sarjeant 1981, pl. 5 figs. 2-3.
Locus typicus: Vossbrook, near Kiel, Germany
Stratum typicum: Kiel beds (Upper Eocene)
Age: Eocene
Translation Klumpp 1953: Sarjeant 1981
Original Diagnosis: Klumpp, 1953, p. 392: Hystrichosphaeridium diktyoplokus ssp. Latum
"A subspecies of the species Hystrichosphaeridium diktyoplokus with the following distinguishing characteristics: most processes are, from their bases, very wide and only the minority are narrow at the bases. These widen towards their outer ends in funnel-like fashion."
---------------------------------------------------------------------------------
Emended Diagnosis: Sarjeant 1981, p. 106-107: Plethysyrinx? latum
Cyst spheroidal to broadly ovoidal, broadly skolochorate to phragmochorate. Surface of phragma punctate to shagreenate. Processes hollow, broadly intratabular to penitabular in situation, cylindrical to buccinate, with fibrous, fenestrate walls. The fibres connect with rootlike extensions surrounding the process bases; the fenestrae are of variable size but never very large and typically have a subquadrate to quadrate outline. Distally the processes widen abruptly and give rise to many irregular prolongations of variable length, having the appearance of an unravelled and stretched woollen sock. They may be linked to adjacent processes by a complete or incomplete investing mesh of trabeculae. Paratabulation: 1-?4", 6", Oc, 5-?6"", ?Op, 1"". Archaeopyle apparently single plate precingular (Type P); operculum free.
Dimensions (holotype): Diameter of cyst (in oblique polar view) c. 70 Ám, length of processes 22-36 Ám.
Description: Sarjeant 1981, p. 106-107: Plethysyrinx? latum
The holotype is folded and proved particularly difficult to interpret; the paratabulation and archaeopyle position, quoted above, are emphatically provisional. The hollow processes might equally be considered as closely interlinked process clusters; their situation appears broadly intratabular rather than penitabular. Despite these difficulties, the form of the processes is so characteristic that this species is readily identifiable (see in particular Pl. 5 fig. 2). The investing trabecula (seen at top in Pl. 5 fig. 3) was not mentioned by KLUMPP and probably taken by her to be an adherent plant fibre.
Discussion. The distinctive nature of the processes of this species clearly characterises it and distinguishes it, not only at specific but also at generic level, from the very different Areosphaeridium diktyoplokus, of which latum was hitherto a subspecies. Cingular processes are certainly lacking; the processes are conspicuously fibrous and fenestrate, with root-like proximal extensions and a partial development of trabecular linkage with adjacent processes. For these reasons this species has been provisionally attributed to Plethysyrinx. However, since the precingular location of the archaeopyle was not confirmed with complete certainty, this generic assignation is very much subject to future review when further specimens become available.
Some similarity may be noted with Cordosphaeridium fibrospinosum DAVEY and WILLIAMS, 1966 (herein provisionally transferred to Emmetrocysta; see p. xxx), which has broad penitabular processes with perforate walls. However, the processes in that species are more exactly cylindrical in shape, perforate rather than fenestrate, and without the l"unravelled" extremities characteristic of Plethysyrinx; moreover, the archaeopyle is considered by DAVEYand WILLlAMS to be "apical haplotabular". It may be that these two species will prove to be congeneric, but I consider it highly unlikely that they will prove conspecific.
Originally Hystrichosphaeridium diktyoplokus ssp. Iatum, subsequently Cordosphaeridium diktyoplokus ssp. Iatum, thirdly Areosphaeridium diktyoplokus ssp. Iatum, fourthly Plethysyrinx lata, fifthly (and now) Cordosphaeridium latum.
Lentin and Williams, 1985, did not accept the emendation of this species by Sarjeant, 1981.
Holotype: Klumpp, 1953, pl.18, figs.8-9; and figured by Sarjeant 1981, pl. 5 figs. 2-3.
Locus typicus: Vossbrook, near Kiel, Germany
Stratum typicum: Kiel beds (Upper Eocene)
Age: Eocene
Translation Klumpp 1953: Sarjeant 1981
Original Diagnosis: Klumpp, 1953, p. 392: Hystrichosphaeridium diktyoplokus ssp. Latum
"A subspecies of the species Hystrichosphaeridium diktyoplokus with the following distinguishing characteristics: most processes are, from their bases, very wide and only the minority are narrow at the bases. These widen towards their outer ends in funnel-like fashion."
---------------------------------------------------------------------------------
Emended Diagnosis: Sarjeant 1981, p. 106-107: Plethysyrinx? latum
Cyst spheroidal to broadly ovoidal, broadly skolochorate to phragmochorate. Surface of phragma punctate to shagreenate. Processes hollow, broadly intratabular to penitabular in situation, cylindrical to buccinate, with fibrous, fenestrate walls. The fibres connect with rootlike extensions surrounding the process bases; the fenestrae are of variable size but never very large and typically have a subquadrate to quadrate outline. Distally the processes widen abruptly and give rise to many irregular prolongations of variable length, having the appearance of an unravelled and stretched woollen sock. They may be linked to adjacent processes by a complete or incomplete investing mesh of trabeculae. Paratabulation: 1-?4", 6", Oc, 5-?6"", ?Op, 1"". Archaeopyle apparently single plate precingular (Type P); operculum free.
Dimensions (holotype): Diameter of cyst (in oblique polar view) c. 70 Ám, length of processes 22-36 Ám.
Description: Sarjeant 1981, p. 106-107: Plethysyrinx? latum
The holotype is folded and proved particularly difficult to interpret; the paratabulation and archaeopyle position, quoted above, are emphatically provisional. The hollow processes might equally be considered as closely interlinked process clusters; their situation appears broadly intratabular rather than penitabular. Despite these difficulties, the form of the processes is so characteristic that this species is readily identifiable (see in particular Pl. 5 fig. 2). The investing trabecula (seen at top in Pl. 5 fig. 3) was not mentioned by KLUMPP and probably taken by her to be an adherent plant fibre.
Discussion. The distinctive nature of the processes of this species clearly characterises it and distinguishes it, not only at specific but also at generic level, from the very different Areosphaeridium diktyoplokus, of which latum was hitherto a subspecies. Cingular processes are certainly lacking; the processes are conspicuously fibrous and fenestrate, with root-like proximal extensions and a partial development of trabecular linkage with adjacent processes. For these reasons this species has been provisionally attributed to Plethysyrinx. However, since the precingular location of the archaeopyle was not confirmed with complete certainty, this generic assignation is very much subject to future review when further specimens become available.
Some similarity may be noted with Cordosphaeridium fibrospinosum DAVEY and WILLIAMS, 1966 (herein provisionally transferred to Emmetrocysta; see p. xxx), which has broad penitabular processes with perforate walls. However, the processes in that species are more exactly cylindrical in shape, perforate rather than fenestrate, and without the l"unravelled" extremities characteristic of Plethysyrinx; moreover, the archaeopyle is considered by DAVEYand WILLlAMS to be "apical haplotabular". It may be that these two species will prove to be congeneric, but I consider it highly unlikely that they will prove conspecific.